The invention relates generally to commercial and residential heating ventilation and air conditioning (HVAC) filtration, and more specifically to a filter that is collapsed to reduce volume during storage and transportation and is readily expanded by the end user before using.
Traditional pleated filters for commercial and residential HVAC systems include one or more frame members and a pleated filtration media attached within the frame members. As is known in the field, the filtration media is commonly pleated to provide greater surface area on, and greater volume in, which to collect particulate. The greater surface area and volume increases the amount of particulate it takes to clog the pores of the media, thereby prolonging the life of the filter. Furthermore, pleated media tends to be stronger than planar media in resisting deformation caused by the force of air passing through the media. However, pleated filters occupy a large volume of empty space per filter due to the shape of the pleated media. While such filters have low weight, they tend to be expensive to transport and store when considering them on a volume basis due to the large amount of empty space per unit volume.
It is known to construct filters of materials that are collapsed by the manufacturer and then expanded and assembled by end users. Such filters have significantly reduced shipping volumes, but require the end user to expand and construct the finished filter so that it can be used in a conventional manner. Conventional collapsible filters require the filter components to depart significantly from traditional non-collapsible filter components at a significant cost and/or structural disadvantage. U.S. Pat. No. 3,938,973 discloses such a prior art collapsible filter, and includes a pinch frame furnace filter that requires a combination of framing materials including heavier paperboard, expensive plastic components and/or adhesive for the end user to assemble. There is also a higher tooling cost with the plastic components, because such components lead to less flexibility on filter sizes available.
Other collapsible filters have been patented. For example, U.S. Pat. No. 9,320,998 shows a collapsible filter that is extremely useful. U.S. Pat. No. 6,652,613 discloses a collapsible filter that has a special frame into which each end of the frame is inserted to retain the expanded shape. U.S. Pat. No. 8,157,881 discloses a collapsible filter onto which special end caps are mounted to retain the filter in the expanded shape.
The need exists for an improved collapsible filter that permits an end user to expand and construct the finished product rapidly, with minimal skill requirements and without the prior art's cost disadvantages.